Over most of the 20th century successive generations of young men and women had steadily rising levels of education. This trend halted abruptly for cohorts born after 1950. The goal of this research project is to understand the reasons for the failure of baby-boom cohorts to maintain the trend set by previous generations, and to analyze the labor market implications of the slowdown in educational attainment. Census and Current Population Survey data sets win be used to document trends in education across cohorts, and evaluate alternative explanations for the post-1950 slowdown. Potential explanations include changes in the economic return to higher education, shifts in the demographic and family background characteristics of children, changes in the accessibility and cost of different forms of higher education, shifts in cohort size that influence the quality and availability of higher education, and changes in military service requirements and veteran education programs. Alternative explanations will be evaluated by comparing changes over time within different states, and also by comparing trends in the U.S. to trends in Canada, the U.K., and Germany, where demographic trends and labor market conditions have been somewhat different. The implications of a shift in the inter-cohort trend in education will be analyzed using models for the demand side of the labor market that explicitly recognize imperfect substitutability between workers of a given education level but different ages. Relative wages of college versus high school workers will be related to age-group specific and economy-wide relative supplies of highly educated labor. The models will be fit to U.S. data, and to data for Canada, the U.K., and Germany, to explore the role of relative supply changes in the observed widening of wage differentials.